Commutable shutoff valve with balanced surfaces for pneumatic apparatus, particularly braking systems



Sept. 3, 1968 G. ALFIERI ETAL 3,399,933

COMMUTABLE SHUTOFF VALVE WITH BALANCED SURFACES FOR PNEUMATIC APPARATUS,PARTICULARLY BRAKING SYSTEMS Original Filed July 12, 1965 2 Sheets-Sheet1 FIG. 7

Sept. 3, 1963 G. ALFIERI ETAL 3,399,933

COMMUTABLE SHUTOFF VALVE WITH BALANCED SURFACES FOR PNEUMATIC APPARATUS.PARTICULARLY BRAKING SYSTEMS Original Filed July 12, 1965 2 Sheets-Sheet2 FIG. 5

I00 a? HM! I Will" INVENTORS GIUSEPPE ALFIERI ROBERTO MORIONDO wymw mT'TORNEYS United States Patent (Mike 3,399,933 COMMUTABLE SHUTOFF VALVEWITH BAL- ANCED SURFACES FOR PNEUMATIC APPA- RATUS, PARTICULARLY BRAKINGSYSTEMS Giuseppe Alfieri and Roberto Moriondo, Milan, Italy, assignorsto Fabbrica Italiana Magneti Marelli S.p.A-, a corporation of ItalyOriginal application July12, 1965, Ser. No. 471,138, Divided and thisapplication Feb. 2, 1967, Ser. No. 630,161

Claims priority, application Italy, July 15, 1964, 49,287/64; Mar. 24,1965, 2,700/65 8 Claims. (Cl. 303-54) ABSTRACT OF THE DISCLOSURE Adistributor for a pneumatic braking system including a first chamberconnected to the braking unit, a second chamber connected to a pneumaticsource and a piston actuated, movable pipe member for selectivelyconnecting the chambers together and the first chamber to an atmosphericexhaust.

The present application is a division of copending application Ser. No.471,138, filed July 12, 1965, which is complementary to application Ser.No. 321,587, filed Nov. 5, 1963, and now abandoned.

While the present application adheres to the inventive principles of theabove-mentioned parent application, it concerns an advantageousembodiment of the balanced shutoff valves which are applicable,particularly in vehicle braking systems, such as, for example,distributors. Specifically, the purpose of this invention is that ofembodying a balanced valve of the specified type, the assembly andmaintenance of which are facilitated and the operation of which isinsured under every aspect, even in the worst operating conditions,which may occur, whilst the seal is insured by gaskets of suitablematerial which may do away with the need to face or secure by adhesivesthe gaskets to the metal parts of the valve itself.

The valve as per this invention embodies a movable pipe member which isaxially urged by spring means and provided with two sealing surfacesengageable with complementary surfaces one of which is represented bythe body of the valve and the other by the means actuating the said pipemember, the valve being characterized by a flange and counterflange onthe periphery of the pipe member to hold a sealing gasket in a resilientco-action condition; by a second flange secured to the valve body and inthe opening of which is inserted the ,pipe member, and whose edgecooperates with the sealing gasket; through a crown secured to one ofthe pipe member ends and which cooperates in sealing relation with thepipe member actuating means, said sealing gasket having an annularcontact surface substantially of the same diameter as the sealingsurface represented by the crown of said pipe member.

The invention also concerns a distributor and a servoauto-distributorprovided with the balanced valves as above described.

The invention will be made clear by the following description taken inconjunction with the attached drawings which illustrate, by way ofexample only some embodiments of the balanced valve forming the objectof this invention.

3,399,933 Patented Sept. 3, 1968 FIGURE 3 is a horizontal cross sectiontaken along line 3-3 of FIG. 1.

The solution describe-d and illustrated makes it possible to avoidsecuring the sealing gaskets to the metal parts and which, especially inthe case of rubber gaskets, could require vulcanizing, in order to beperfect and undetachable. On the other hand, it is possible to replacethe gaskets quickly when necessary, Without need of replacing also metalparts of the balanced valve with reference to FIGS. 1 to 3, theservo-auto-distributor illustrated embodies a housing 10 which has inits inner part, a sleeve 12 which is secured and held in a sealed tightrelationships against a shoulder 14 by a cover 16 secured to the housingby means of bolts 18. The sleeve 12 has on its inner part aflange 20 andabove the latter a split crown 22 which form a guiding element for apipe member 24 which represents the moving element of the valve of thisinvention. The pipe member has, at its upper end, a crown 26(representing one of the two sealing surfaces of said movable element)and near to said crown, a flange 28 one of whose faces is recessed toreceive the annular gasket (ring gasket) 30, which is toroidal in thecase illustrated. The gasket 30 is held and secured conveniently by aflange 32 embodying a bushing 34 inserted about the lower end of pipemember 24 and secured there by a split ring 36 which partially engages aperipheral groove around the edge of said pipe member 24. A sealinggasket 38 is located between the bushing 34 and the inner wall of thesleeve 12 to further guide the pipe member 24, and is held by means of aring 40 by the bottom cover 16, previously considered; moreover, thegasket 38 carries one of the ends of a helical spring 42 the other endof which engages flange 32 thus urging the toroidal gasket 30 againstthe sealing flange 20 The housing 10 of the servo-auto-distributor has,toward its upper part, a first cylinder 44 for a relevant piston 46provided with sealing gaskets, one of which consists of a disk 48 withflexible edges and which has, in its central part, a circular backingplate 50 suitable to cooperate with the previously mentioned crown 26and which represents the movable sealing seat of the valve of thisinvention. The disk 48 is held in engagement with the piston 46 by theaction of a spring 47 the other end of which is held by the sleeve 12.

A stem -52 is secured to the piston 46 which slides into engagement withthe bottom of a blind hole carried, axially, by a second stem 54 securedto a second piston 56 which is co-axial with piston 46 and which movesin a relevant cylinder 58 which is an extension of cylinder 44. Thesecylinders 44 and 58 are separated from each other by a wall 60 whichhas, in its central part, an opening suitable for housing a gasket 62which cooperates with the stem 54.

The piston 56 is provided with an opening, the upper edge of which formsa sealing seat 64 for a valve 66 urged by a spring 68, the action ofwhich biases said valve away from its seat, causing it to engage with anannular stop 70 in agroove in the body of piston 56 so as to keep valve66 slightly detached from its seat 64. The cylinder 58 is closed by acover 72 which has a drilled lug 74 in its middle portion and whichhouses a manually actuated shutoff device consisting of a rod 76 one ofthe ends of which is provided with two coaxial pistons 78 and 79separated by a peripheral groove (see FIG. 2).

Said two pistons cooperate alternately with respective sealing gaskets80 and 81 located inside the drilled lug 74 and secured thereto by asplit segment 84 through a suitable spacer 82.

A spring 85 is inserted on rod 76 so as to urge the double piston 78-79from left to right (FIGURE 2) and is secured at its other end by abushing 86 inserted in the hole of lu-g 74 and held therein by a cover88.

The protruding end of rod 76 carries an actuating handle 90 or remotecontrol transmission elements comprising, for example, tie rods, Bowdencables or similar devices connected to a control lever. The hub of thishandle has, in a convenient position, a lug 91 which fits into arelevant seat in the cover 88 and which may be disengaged from said seatto position, axially, the double piston 78 and 79.

The parts described in connection with the servo-autodistributor giveuse to a plurality of chambers pneumatically connected to each other andto the trailer braking system. Specifically, the annular chamber A,formed inside housing by sleeve 12 communicates through a fitting 92with a compressed air tank located on the trailer, in turn connected, inthe known manner, with the compressed air supply source through the automatic braking system conduit. Chamber A is also connected, through aconduit 94 (see FIGURE 2) with an annular chamber B formed by thegaskets 80-81 inside the drilled lug 74 when the double piston 78-79 isin the position shown in FIGURE 2.

On the other hand, when the double piston is shifted toward the left,chamber B is made communicant with the atmosphere through a vent hole 95located in a suitable position in lug 74; moreover, said chamber B isconstantly in communication with chamber C pertaining to thecylinder-piston assembly 56-58, through a vent hole 96 in cover 72.

Chamber C is connected with a further chamber D in the cylinder-pistonassembly 56-58 through a retaining valve 66, said chamber D beingcommunicant through fitting 55 which receives the conduit for automaticbraking in relation to what will be described hereinafter.

The upper chamber F of piston cylinder assembly 44-46 is connected, byfitting 45 with the adjustable braking conduit, which is, in turn,connected to the braking system distributor; the underlying chamber G,on the other hand, is permanently connected with a rectilinear chamber98 which forms a manifold and which holds axially, a cross-piece 100(see FIGURE 3) secured to the housing 10 and arranged perpendicularly inrespect to the latter; said cross-piece has, along one of its generatinglines, fittings 102 which receive the pipes leading to the brakeactuating devices.

Chamber G communicates with the atmosphere through the opening in pipemember 24 and the holes in bottom cover 16, when the bottom plate 50 isdisengaged from crown 26, and with chamber A through the slits in guidecrown 22 when the gasket 30 is moved away from flange 20.

The operation of the servo-auto-distri-butor described infra is evident.When the brake actuating devices are in their normal idle position, thepressure prevailing in the automatic braking conduit and which isconnected to fitting 55 is delivered to chamber D and, through theholding valve 66, (when open) passes into chamber C and the piston 56 isheld in the lifted position only by the action of spring 57. Saidpressure in chamber C, passes through vent 96, chamber B conduit 94,chamber A and fitting 92 into the trailer tank, since the double piston78-79 is in the position shown in FIG- URE 2, to establish communicationbetween chamber B and conduit 94.

Under these conditions, if the distributor installed on the motorvehicle is actuated, in the modulating braking conduit connected tofitting 45, air flow is delivered into chamber F which displaces piston46 in opposition to the action of spring 47. The circular bottom plate50 engages with the crown 26 of pipe member 24 to shut off thecommunication between chamber G and the atmosphere; on the other hand,the gasket 30 is disengaged from flange 20 to establish a communicationbetween said chamber G and chamber A. Furthermore, the compressed airfrom the trailer tank is delivered, through fittings 107 to the brakingdevices, so that the latter may be actuated. When the control action onthe distributor ceases, the adjustable braking pipe and consequentlyalso chamber F are made communicant with the atmosphere and spring 47causes piston 46 to return to its lifted position, to shut off, on theone hand, a communication between chambers A and G and on the other, toestablish communication of chamber G with the atmosphere.

During emergency braking (which is effected by discharging the pressurein the automatic braking pipe), the pressure prevailing in chamber B isannulled and piston 56 is therefore subjected only to the action of thepressure prevailing in chamber C, which is supplied by the pressure inthe trailer tank. As soon as the pressure in chamber D 'drops, theprevailing pressure in chamber C closes the retaining valve 66 and actson piston 56, displacing the latter in opposition to the action ofspring 57.

The displacement of this piston, through stem 54, also causes piston 46to shift establishing thereby the pneumatic connection previouslyconsidered, and resulting operation of the trailer brakes.

When the trailer is separated from the motor vehicle, with consequentinterruption of the automatic braking conduit, the conditions justconsidered are repeated and the trailer brakes are actuatedautomatically. To release the brakes of the trailer when separated fromthe motor vehicle, the handle is actuated to shift axially the rod 76with its double piston 79-78, in opposition to the action of spring 85.The piston 79 engages with the gasket 81 to interrupt the communicationbetween the trailer tank and chamber B, whilst the latter, is connectedto the atmosphere, through the slot in the piston 78 and hole 95.

Meanwhile, equal pressures are established in chambers C and D andpiston 56, is returned to its initial position, together with piston 46,through the action of springs 57 and 47, respectively. The pipe member24 is also returned to its initial position, thereby interrupting thecommunication between chambers A and G, whilst the latter chamber isconnected with the atmosphere to render the trailer braking devicesinoperative.

The double piston 78-79 may be maintained permanently in the positionlast considered by disengaging lug 91 from its seat in cover 88, whilstengaging it with the external surface of the latter.

In view of the above description, taken in conjunction with thedrawings, the advantages obtainable with the servo-auto-distributorshould be evident to all those skilled in the art.

The horizontal arrangement of the fittings 102 for the brake actuatingmeans, makes it possible to obtain wide ports for allowing air to pass,without requiring an increase in dimensions and especially the height ofthe servo-auto-dist-ributor.

The increased power of the servo-auto-distributor, or the ratio betweenthe effective active areas of piston 46- 48 is achieved by suitablysizing the diameter of crown 26 in pipe member 24.

The area formed by said crown is substantially equal to the area formedby flange 20 in sleeve 12 and which represents a fixed seat for thevalve shutting off communication between chambers A and G.

It is understood that modifications and changes may be introduced in thebalanced valve, the distributor and servo-auto-distributor hereinabovedescribed, for the purpose of meeting with the application and usagerequirements, without departing from the scope of this invention.

Weclaim:

1. A distributor device for pneumatic systems comprising a casing, firstand second chambers formed within said casing, an inlet and an outlet insaid first chamber connected to a modulated ,braking circuit, a firstpassageway within said first chamber connecting said inlet with saidoutlet, a second passageway within said first chamber connecting saidoutlet with the atmosphere, a pipe member movably mounted within saidfirst chamber, 21 first sealing means associated with said pipe memberfor blocking said first passageway when said pipe member is in oneposition, said second passageway being normally open when said pipemember is in said one position, first piston means mounted in said firstchamber and being slidably mounted for movement axially of said pipemember, a second sealing means associated with said first piston meansand said pipe member for blocking said second passageway when said firstpiston means is moved in contact with said pipe member, said firstpiston means being movable to press said pipe member to another positionwherein said first passageway is opened, a second piston movably mountedin said second chamber, conduit means connecting said second chamber toan automatic braking conduit and a source of fluid under pressure, saidsecond piston including means extending between said first and secondchambers for actuating said first piston means, an annular sealing seatin said first chamber, said first sealing means including a sealing ringwhich bears against said annular seat in its one side and engages saidpipe member on its other side to provide sealing therebetween, saidfirst sealing means and said second sealing means being substantially ofthe same diameter, retaining means for holding said pipe member withinsaid casing, spring means mounted between said retaining means and saidfirst sealing means for urging said sealing ring against said annularseat, said movable pipe member further comprising a flange, a counterflange carried by the periphery of the pipe member so as to hold saidsealing ring therebetween for coaction with said annular sealing seat ofsaid casing and in whose opening said pipe member is inserted and theedge of which engages with said sealing ring; a crown secured to one endof the pipe member, a gasket on said actuating means engaging with saidcrown, said sealing ring having an annular contact surface which issubstantially of the same diameter as the sealing surface of said crown.

2. A distributor device according to claim 1 in which said first pistonmeans comprises a disk provided with an axially extending first sternand at least one annular sealing diaphragm, said diaphragm having at itscentral part circular lug forming a'seat which cooperates in a sealingrelation with said pipe member.

3. A distributor device according to claim 2 in which said second pistonmeans has an axially depending, holl-ow second stem, said first andsecond stems interengaging to form a stop for said first piston in onlyone direction of movement.

4. A distributor device according to claim 1 in which said second pistonis provided with a spring biased retaining valve which controlscommuncation between first and second portions of said second chamber.

5. A distributor device according to claim 1 in which said casingfurther comprises a manifold chamber the axis of which is substantiallyhorizontal with respect to the longitudinal axis of said device, aplurality of pipe fittings in said manifold chamber for connection to aplurality of fluid brake actuating means.

6. A distributor device according to claim 1 in which said casing has acover closing the end adjacent said second chamber, said covercomprising a substantially diametrical hollow lug, double piston meansslidably mounted in said lug and axially movable between two operativepositions, said double piston in a first position controllingcommunication of said second chamber with a source of fluid underpressure and in a second position controlling communication of saidsecond chamber with the atmosphere.

7. A distributor device according to claim 6 in which said double pistonmeans is manually operable.

8. A distributor device according to claim 6 in which annular gasketmeans are provided in said hollow lug to provide sealing means for saiddouble piston in its operative positions.

12/1966 Bueler 303-52 5/1965 Bueler 30354 XR

